Problem: Khan.scratchpad.disable(); For every level Christopher completes in his favorite game, he earns $310$ points. Christopher already has $200$ points in the game and wants to end up with at least $2700$ points before he goes to bed. What is the minimum number of complete levels that Christopher needs to complete to reach his goal?
Answer: To solve this, let's set up an expression to show how many points Christopher will have after each level. Number of points $=$ $ $ Levels completed $\times$ Points per level $+$ Starting points Since Christopher wants to have at least $2700$ points before going to bed, we can set up an inequality. Number of points $\geq 2700$ Levels completed $\times$ Points per level $+$ Starting points $\geq 2700$ We are solving for the number of levels to be completed, so let the number of levels be represented by the variable $x$ We can now plug in: $x \cdot 310 + 200 \geq 2700$ $ x \cdot 310 \geq 2700 - 200 $ $ x \cdot 310 \geq 2500 $ $x \geq \dfrac{2500}{310} \approx 8.06$ Since Christopher won't get points unless he completes the entire level, we round $8.06$ up to $9$ Christopher must complete at least 9 levels.